This invention relates to an eye examining apparatus, and more particularly to an eye examining apparatus for measuring the optical transfer function of an optical system of a patient's eye.
An abnormality detecting apparatus for detecting abnormality in an optical system of a patient's eye caused by opacity of the lens or vitreous body of the patient's eye or the like by detecting the amount of reflected light, utilizing a refraction measurement system for measuring the refraction of a patient's eye, has heretofore been known as an eye examining apparatus.
As a method for examining abnormality in the optical system of an eye, a method has also been proposed or measuring the refraction across any possible diameter of a patient's eye and inferring abnormality in the optical system of the patient's eye from the scattering of these measured values.
In the above-described conventional eye examining apparatus, however, if there is opacity in the common region where both the light beam which enters the retina and the light beam reflected from the retina pass, the light beam reflected from the opacity mixes with the light beam reflected from the retina. As a result, this opacity may not be detected as abnormality in an abnormality detecting system which detects opacity of a body subject to light transmission.
Furthermore, in the method of detecting abnormality of the optical system of an eye, when opacity is generated in the vicinity of the retina of the patient's eye, the opacity has an influence on the refraction in the direction of relevant diameter, but if opacity is generated in the vicinity of the pupil, the light beam to be measured in all diametric directions passes through the opacity, so that there is no scattering of the measured values with respect to each diameter, which inconveniently makes it impossible to detect the opacity.